An Indiana Little League coach accused of threatening national security by teaching government job applicants how to beat lie detector tests was sentenced Friday to eight months in prison.

Prosecutors asked a federal judge to send a “strong message” by sentencing Chad Dixon to prison in their unprecedented crackdown aimed at deterring other such polygraph instructors. They described Dixon as a “master of deceit” who taught as many as 100 people – including child molesters, intelligence employees and law enforcement applicants – how to beat lie detectors.

U.S. District Judge Liam O’Grady’s sentence bolsters federal authorities’ pursuit of similar cases. Despite prosecutors’ depiction of Dixon’s conduct as “dangerous,” the case sparked a debate over whether the federal government should be pursuing such instructors given questions about the reliability of lie detectors, which are not accepted by most courts as evidence against criminal defendants.

Prosecutors, who had asked for almost two years in prison, said Dixon crossed the line between free speech protected under the First Amendment and criminal conduct when he told some of his clients to conceal what he taught them while undergoing government polygraphs. Dixon, 34, pleaded guilty late last year to charges of obstruction and wire fraud after federal agents targeted him in an undercover sting.

O’Grady acknowledged “the gray areas” between the constitutional right to discuss the techniques and the crime of teaching someone to lie while undergoing a government polygraph.

“There’s nothing unlawful about maybe 95 percent of the business he conducted,” the judge said.

However, O’Grady added he felt that “a sentence of incarceration is absolutely necessary to deter others.”

According to prosecutors, Dixon trained seven federal law enforcement applicants and two government contractors with security clearances – one with the FBI and one with an unnamed intelligence agency.

Prosecutors also cited Dixon’s interactions with two undercover agents. Dixon, for instance, advised one undercover agent posing as the brother of a violent Mexican drug trafficker to withhold details during a polygraph for a U.S. Customs and Border Protection job, prosecutors said. They listed nine unnamed sex offenders Dixon trained across the country as actions the judge “must consider.”

“This crime matters because what he did endangers others,” said Anthony Phillips, a prosecutor with the Justice Department’s division that pursues corrupt public officials. “That’s not the government putting the spin on anything. . . . This is not hyperbole. . . . Mr. Dixon’s crimes should matter to all Americans.”

Dixon’s defense attorney, Nina Ginsberg, accused prosecutors of trying to turn her client into a “poster child for its newly undertaken campaign” to stop people from using the techniques. While she acknowledged that her client earned about $1,000 a session for teaching as many as 70 people over a year and a half, she said he was mostly teaching people how to pass polygraph tests demanded by spouses who suspected infidelity.

“It is not a crime to teach people to lie on a polygraph test,” Ginsberg said. “Mr. Dixon gave them advice. He didn’t know that they were going to follow that advice.”

O’Grady expressed sympathy for Dixon, whom he said appeared to have started training people because of financial troubles related to an electrical contracting business.

“This is so unfortunate,” he said, adding, “I’m not worried that you’re going to commit another offense of this nature.”

But the judge said he felt compelled to take the crime seriously because Dixon’s motivation was greed.

“He made the decision to move into this line of business,” he said.

O’Grady sentenced Dixon to eight months on each count but allowed the sentences to be served concurrently. The judge also imposed three years of supervised release following the prison term.

Prosecutors and a Customs and Border Protection agent assigned to the case declined to respond to questions outside the courtroom, including whether they plan to indict any other instructors.

Agents separately targeted Doug Williams, a former Oklahoma City police polygrapher, but have refused to say whether they gathered evidence of a crime. Williams, who has been teaching the techniques for three decades, has said he has done nothing wrong.

McClatchy reported last month that investigators confiscated business records from Dixon and Williams. The records included the names of as many as 5,000 people who’d sought polygraph-beating advice. U.S. agencies have determined that at least 20 of them applied for government and federal contracting jobs, and at least half of that group was hired, including by the National Security Agency.

Phillips, one of the prosecutors in the case, said Dixon’s clients passed polygraphs after repeatedly failing them.

“This training worked,” he said in court.

Scientists, however, have long questioned whether polygraphers can reliably identify liars. Researchers say the polygraph-beating techniques can’t be detected or taught with certainty, either.

Polygraphers interpret measurements of blood pressure, sweat activity, respiration and movement to identify people who lie or try to beat the test. The instructors, meanwhile, claim to teach methods that help the test takers avoid such scrutiny. The techniques, known as countermeasures, include controlled breathing, muscle tensing, tongue biting and mental arithmetic.

Despite federal scrutiny of the techniques, online traffic to a website that offers countermeasure tips has surged since news of the prosecution, according to the site’s owner, George Maschke.